1. Field of the Invention
The present invention relates to a method of recognizing proximity of an object in mobile terminal. More particularly, the present invention relates to an apparatus and method for recognizing proximity of an object using a proximity sensor in a mobile terminal.
2. Description of the Related Art
Nowadays, a mobile terminal is very widely used. The widespread use of the mobile terminal is based on its ability to provide various data transmission services and additional services as well as intrinsic voice communication and multimedia communication appliance services. Based on the various services that can be provided by the mobile terminal, User Interface (UI) technology that controls the mobile terminal has also been continuously developed.
Currently, a mobile terminal having a proximity sensor is available, and the mobile terminal performs a predefined function by recognizing whether a user approaches the mobile terminal. A conventional function of the mobile terminal using proximity recognition is a screen locking and release function. When a user performs communication using a mobile terminal, the mobile terminal generally contacts an ear or a cheek of the user. In a touch screen based-mobile terminal, an unintended key may be input due to a contact with the user's ear or cheek. Accordingly, the proximity sensor recognizes the proximity of the user (when an earpiece portion is hidden) such that, when the user approaches the mobile terminal, a screen locking function is executed, and when the user recedes from the mobile terminal, a screen locking function is released and thus an input of an unintended key is prevented. The proximity sensor generally uses a photodiode-based proximity sensor.
FIG. 1 is a diagram illustrating a photodiode-based proximity sensor according to the related art.
The proximity sensor 100 includes a light emitting unit 103 and a light receiving unit 105. The light emitting unit 103 may be configured with a Light Emitting Diode (LED), and the light receiving unit 105 may be configured with a photodiode. When the light emitting unit 103 projects light, the projected light is reflected by an object approaching the proximity sensor, and the reflected light is transferred to the light receiving unit 105. The light receiving unit 105 recognizes that an object approaches the proximity sensor by absorbing the transferred light. The light receiving unit 105 generates data of an amount (light receiving amount) corresponding to the amount of absorbed light, and the generated data are used for determining the degree to which an object approaches the proximity sensor.
The mobile terminal having an available proximity sensor has a reference value of a light receiving amount necessary for proximity recognition of an object. The reference value is set based on a predefined distance between the proximity sensor and the object. That is, the proximity sensor should absorb an amount of light equal to the light receiving amount reference value at the predefined distance.
However, the proximity sensor can absorb a light receiving amount of a value different from the reference value in a situation where an object is disposed at the predefined distance according to the surrounding environment (such as temperature, humidity, pressing, and an impact), a noise characteristic of the proximity sensor (noise characteristic of the light receiving unit or the light emitting unit), and extended use for a long time. That is, even if the object approaches the proximity sensor at the same distance, the mobile terminal may or may not recognize proximity of the object.
Further, conventionally, when manufacturing a mobile terminal, a failure of the proximity sensor is determined by measuring whether the proximity sensor absorbs light of a predefined amount at a predefined distance, and a proximity sensor that does not satisfy the reference is processed as a failure. A yield rate of the proximity sensor is deteriorated by the proximity sensor processed as a failure.